The present invention generally relates to a pin array assembly and method of manufacture; and more particularly relates to a single crystal silicon pin array assembly and method of manufacture of the single crystal silicon pin array assembly.
Current pin array assemblies used to transfer material from a reservoir to another surface substrate such as a membrane or a lay out of gel micro matrices are subject to deformation during the loading process. As a result of bending of the individual pins, problems with the solution transfer result. A need exists for very precise solution transfer and that the resulting geometry of the solutions on the substrate will be uniform. In addition to spacing requirements of the pins in the pin assembly, there are also certain chemical characteristics that are very important. For example, it is necessary that the pin ends that come in contact with the solutions, are hydrophilic; while the sides of each pen must be hydrophobic. These requirements restrict the drop of solution to the end of the pin, so that there is no danger that the drop of solution will roll down the sides of a pin in the array.
A principal object of the present invention is to provide an improved pin array assembly and method of manufacture of the pin array assembly.
It is another object of the present invention to provide such an improved pin array assembly and method of manufacture of the pin array assembly where the potential for bending of individual pins is minimized.
It is another object of the present invention to provide such an improved pin array assembly and method of manufacture of the pin array assembly enabling very precise solution transfer and generally uniform geometry of the solutions on the pin array assembly.
It is another object of the present invention to provide such an improved pin array assembly and method of manufacture of the pin array assembly where pin ends are hydrophilic while pin sides are hydrophobic.
It is another object of the present invention to provide such an improved pin array assembly and method of manufacture of the pin array assembly where the pin array assembly is generally easy to make.
In brief, an improved pin array assembly and method of manufacture of the pin array assembly are provided. A pin array assembly includes a single crystal silicon wafer. The single crystal silicon wafer defines a base and an array of pins. Each of the pins has a shaft and a tip surface. The pin shaft is hydrophobic and the pin tip surface is hydrophilic.
The method of manufacture of the pin array assembly includes the steps of forming an initial shape of a single crystal silicon wafer to define a base and an array of pins. The initial shape of a single crystal silicon wafer is etched and the array of pins is polished.
In accordance with features of the invention, the step of forming an initial shape of a single crystal silicon wafer to define a base and an array of pins includes mechanically sawing the single crystal silicon wafer to define a base and an array of pins. Potting of the pin array in wax allows all pins to be made the same length and also allows the plane of the tips of the pins to be made coplanar with the base. Chemical treatment of the pins is performed to make the shaft of the pins hydrophobic and to make the tip surfaces hydrophilic.